Membrane element that encodes raw video frames to H265 format.

The element expects each frame to be received in a separate buffer, so the parser (Membrane.Element.RawVideo.Parser) may be required in a pipeline before the encoder (e.g. when input is read from Membrane.File.Source).

Additionally, the encoder has to receive proper stream_format with picture format and dimensions before any encoding takes place.

Please check t/0 for available options.

Element options

Passed via struct Membrane.H265.FFmpeg.Encoder.t/0

• crf

  0..51

  Default value: 28
  Constant rate factor that affects the quality of output stream. Value of 0 is lossless compression while 51 offers the worst quality. The range is exponential, so increasing the CRF value +6 results in roughly half the bitrate / file size, while -6 leads to roughly twice the bitrate.

• preset

  preset()

  Default value: :medium
  Collection of predefined options providing certain encoding. The slower the preset chosen, the higher compression for the same quality can be achieved.

• profile

  H265.profile_t() | nil

  Default value: nil
  Sets a limit on the features that the encoder will use to the ones supported in a provided H265 profile. Said features will have to be supported by the decoder in order to decode the resulting video. It may override other, more specific options affecting compression.

• tune

  tune() | nil

  Default value: nil
  Optionally tune the encoder settings for a particular type of source or situation. See x265 encoder's man page for more info. Available options are:

  • :grain - preserves the grain structure in old, grainy film material
  • :fastdecode - allows faster decoding by disabling certain filters
  • :zerolatency - good for fast encoding and low-latency streaming

• use_shm?

  boolean()

  Default value: false
  If true, native encoder will use shared memory (via Shmex.t/0) for storing frames

• max_b_frames

  non_neg_integer() | nil

  Default value: nil
  Maximum number of B-frames between non-B-frames. Set to 0 to encode video without b-frames

• gop_size

  non_neg_integer() | nil

  Default value: nil
  Number of frames in a group of pictures.

• x265_params

  binary()

  Default value: ""
  Set x265 options using a list of key=value couples separated by ":". See x265 --help for a list of options.

Pads

:input

Accepted formats:

%RawVideo{pixel_format: format, aligned: true} when format in [:I420, :I422]

:output

Accepted formats:

%H265{alignment: :au}